Maskless lithography for versatile and low cost fabrication of polymer based micro optical structures

authored by
Muhammad Shaukat Khan, Roland Lachmayer, Bernhard Roth
Abstract

For applications in optical communication, sensing or information projection in automotive lighting, polymer based optical devices are of keen interest. Optical structures such as waveguides and gratings are basic blocks for these devices. We report on a simple, versatile, and yet low-cost fabrication method suited for both binary and multilevel diffractive microstructures as well as multimode optical waveguides in polymers. The fabrication of the diffractive structures, i.e. gratings, with two and multiple levels, is achieved by using a maskless optical lithography system employing a spatial light modulator. With the same system, waveguide cladding structures are realized by stitching of multiple single exposure patterns. For replication of these structures on polymer, e.g. polymethyl methacrylate (PMMA), a lab-made hot embossing machine is used. We then employ UV curable material and doctor blading to realize the waveguide cores. The created diffractive and waveguide structures are characterized in terms of diffraction efficiency and optical propagation loss, respectively, showing good optical quality and performance. With our fabrication system we have demonstrated a diffraction efficiency of 71% for multilevel grating structure and a propagation loss for stitched waveguides of 2.07 dB/cm at a wavelength of 638 nm. These basic elements will be employed to realize entire optical measurement systems for applications in sensing and integrated photonics in the next step.

Organisation(s)
Institute of Motion Engineering and Mechanism Design
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Hannover Centre for Optical Technologies (HOT)
Type
Article
Journal
OSA Continuum
Volume
3
Pages
2808-2816
No. of pages
9
ISSN
2578-7519
Publication date
15.10.2020
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering
Electronic version(s)
https://doi.org/10.1364/OSAC.400056 (Access: Open)